Imitation leather material

ABSTRACT

THIS INVENTION PROVIDES AN IMITATION LEATHER HAVING IMPROVED POROSITY AND CAPACITY TO ABSORB MOISTURE. THE MATERIAL OF THIS INVENTION COMPRISES AT LEAST ONE LAYER OF A TEXTILE SHEET MATERIAL EACH SANDWICH BETWEEN TWO LAYERS OF FIBROUS FLOCK PERMEATED WITH A BINDING AGENT, THE TEXTILE SHEET MATERIAL ALSO BEING PERMEATED BY A BINDING AGENT AND THE FLOCK LAYERS BEING HELD TOGETHER BU Y A FLOCK BINDER MATERIAL.

y 1974 I J. HEFELE' I IHITATION LEATHER MATERIAL Filed latch 20, 1972 nited States Patent Oifice 3,822,174 IMITATION LEATHER MATERIAL Josef Hefele, Grafeling, Germany, assignor to Kufner Textilwerke KG, Munich, Germany Filed Mar. 20, 1972, Ser. No. 236,058 Claims priority, application Germany, Mar. 22, 1971, P 21 13 790.6 Int. Cl. D03d 27/00 US. Cl. 161-82 12 Claims ABSTRACT OF THE DISCLOSURE This invention provides an imitation leather having improved porosity and capacity to absorb moisture. The material of this invention comprises at least one layer of a textile sheet material each sandwiched between two layers of fibrous flock permeated with a binding agent, the textile sheet material also being permeated by a binding agent and the flock layers being held together by a flock binder material.

BACKGROUND OF THE INVENTION This invention relates to imitation leather materials made from flocked textile sheet materials and binding agents.

Previously known imitation leathers dilfer from material leather principally in that they have insufiicient capacity to absorb moisture. Articles of clothing such as shoes made from such imitation leather are uncomfortable to wear because the material soon reaches its limit of moisture absorption.

The object of the present invention is to provide an imitation leather material having improved porosity and capacity to absorb moisture.

SUMMARY According to the present invention, there is provided a porous, imitation leather material which comprises at least one layer of a textile sheet material each sandwiched between two layers of fibrous flock permeated with a binding agent, the textile sheet material also being permeated by a binding agent and the flock layers being held together by a flock binder material.

BRIEF DESCRIPTION OF THE DRAWINGS The single figure of the accompanying drawings illustrates a preferred embodiment of the imitation leather material according to the invention.

DETAILED DESCRIPTION OF THE INVENTION It is already known to make imitation leather by flocking textile substrates using flock binders. These known materials differ from the material of this invention in that the flocked material usually has a nap or pile which is free from binding agent projecting beyond the flock binder and in that the layer of flock covers the textile substrate on one side only.

A preferred imitation leather according to this invention has a single textile sheet sandwiched between two flock layers. The flock fibres are suitably less than 2 mm. long, preferably less than 1 mm. long. While the preferred textile material is woven or knitted, any other suitable textile material such as non-woven or stretch-bonded material may be used.

The textile material is preferably formed of synthetic fibres such as polyamide, polyester or polyacrylic fibres. Suitably, continuous filaments with a fibre size of 1.0 to 6.0 denier are worked into single or double knitted material on raschel knitting machines.

3,822,174 Patented July 2, 1974 urethancs or reactive polymethacrylates. Other elastic binding agents such as acrylonitrile-butadiene-styrene c0- polymers, which are applied in solution or dispersion, may also be used. The same or similar materials may be used as the flock binder.

Instead of two layers of flock and an embedded textile material, the imitation leather may consist of several layers of flock and several layers of textile material. For example three layers of flock may have sandwiched between them two layers of textile material in the sequence: flock layer-textile layer-flock layer-textile layer-flock layer.

The imitation leather may be prepared, for example, in the following manner:

A thin layer of a polyurethane-forming mixture of prepolymerised polyurethane having terminal hydroxyl groups, a tri-isocyanate and an accelerator dissolved in up to about 10% trichlorethylene is applied by painting or brushing on a smooth or patterned substrate to which polyurethane does not adhere, such as a siliconised paper. Wool flock 0.5 mm. in length is applied electrostatically to this painted-on layer serving as flock binder with the assistance of a beater to assist penetration of the flock into the binder. The excess flock is then sucked off but the adhering flock is pressed on, dried and covered with a thickly painted-on polyurethane-forming mixture as binding agent.

A sheet of single closely woven or knitted polyamide filaments having a weight of about g. per square meter is embedded in this second painted-on application penetrating the layer of flock and is tightly pressed onto the covered substrate. After evaporating the solvent, the laminated woven material is covered with a painted-on third layer of a polyurethane-forming mixture. A dense layer of flock is applied to this layer by electrostatic means with the help of a heater and the excess flock is sucked off. The flock is again pressed on and, after evaporating the solvent, the last layer of binding agent is painted on this layer of flock.

By leaving the material at room temperature for a period or by leaving at a higher temperature for a shorter period if the binding agent is condensed into polyurethane, any residual solvent is evaporated.

The imitation leather is now stripped 01f from the substrate and on one side has a mirror image of the texture or smoothness of the substrate surface but is permeated with numerous capillaries. The other side of the imitation leather has the appearance of suede and also has a particularly high number of capillaries.

By adding pigment or dye to the binding agent and by dying the fibrous flock and the textile material, the imitation leather can be rendered in any desired colour. Preferably the imitation leather consists of about 180 grm. of flock, grm. of binder and 75 grm. of woven or knitted material per sq. meter and has a thickness of about 0.7- 0.8 mm.

By subsequently impregnating the material with a watery liquor containing a small amount of water-soluble polyamide, the degree of absorptivity of the imitation leather can be increased. Such impregnated imitation leather having a rayon flock in its flock layer readily absorbs drops of water on its suede side in a few seconds and is dry to the touch after absorbing the water. The ability to absorb moisture is about three times as high as with previously known imitation leather and reaches about 20% in an atmosphere substantially saturated with water vapour. The imitation leather is particularly suitable as an inner lining for shoes. When provided with a thicker surface layer, which may, for example, consist of microporous polyurethane or foamed PVC, the imitation leather may also be used as a synthetic uppers material. Other possible uses are for upholstery, bags and luggage.

In the embodiment illustrated in the drawing, the imitation leather material comprises a knitted material 4 formed of synthetic fibres sandwiched between two slightly compressed flock layers 1 and 2 permeated by a binding agent 3. Another binding agent 5 permeates textile layer 4.

I claim:

1. In a porous imitation leather material which comprises a layer of textile sheet material sandwiched between two layers of fibrous flock permeated with a binding agent, the textile sheet also being permeated by a binding agent and the flock materials being held together by a flock binder material, the improvements which consist in the textile sheet material being a material knitted from a synthetic fiber and one surface of the imitation leather being smooth or textured and permeated by capillaries and the other being of suede-like appearance and permeated by capillaries.

2. A material according to Claim 1 wherein the flock fibres are less than 2 mm. in length, preferably less than 1 mm.

3. A material according to Claim 1 wherein the fibrous flock includes at least one fibrous material selected from the group consisting of natural cellulose fibres, regenerated cellulose fibres, wool fibres and collagen fibres.

4. A material according to Claim 1 wherein the binding agent is selected from the group consisting of polyurethanes, polymethacrylates and acrylonitrile-butadienestyrene copolymers.

5. A porous imitation leather as claimed in Claim 1 where one surface is a smooth surface and the other has the appearance of suede.

6. A material according to Claim 1 which is impregnated with a water soluble polyamide.

7. A method of forming a porous imitation leather material which comprises the steps of:

(a) brushing a layer of flock binder on to a substrate to which the binder does not adhere;

(b) electrostatically applying fibrous flock to the flock binder to embed one end of the flock fibres in the flock binder;

(c) applying a layer of the flock binding agent to the flock layer;

(d) applying to and pressing into the layer of binding ggent a textile sheet material knitted from synthetic bres;

(e) applying a layer of flock binder to the said textile sheet;

(f) electrostatically applying fibrous flock to the flock binder to embed one end of the flock fibres in the flock, binder;

(g) applying a layer of binding agent to the flock layer and, if so desired;

(h) repeating steps (d), (e), (f) and (g) at least once.

8. A method according to Claim 7 wherein the flock fibres are less than 2 mm. in length, preferably less than 1 mm.

9. A method according to Claim 7 wherein the fibrous flock includes at least one fibrous material selected from the group consisting of natural cellulose fibres, regenerated cellulose fibres, wool fibres and collagen fibres.

10. A method according to Claim 7 wherein the binding agent is selected from the group consisting of polyurethanes, polymethacrylates and acrylonitrile-butadienestyrene copolymers.

11. A method as claimed in Claim 7 where the porous imitation leather is subsequently impregnated with an aqueous solution of a water-soluble polyamide.

12. A method according to Claim 7 which comprises the further step of impregnating the porous imitation leather with a watery liquor containing a water soluble polyamide.

References Cited UNITED STATES PATENTS 2,071,626 2/ 1937 Harris 1177 3,592,719 7/1971 Ofiray 16164 3,573,121 3/1971 Fukada 161Dig. 2 3,684,637 8/1972 Anderson 161-64 MARION E. McCAMISH, Primary Examiner US. Cl. X.R.

117-26; 161-64, 89, 170, Dig. 2 

